Heat sink



FIG. 1 is a perspective view of the top, front and left side of a heat sink showing our new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a back elevational view thereof;

FIG. 4 is a left elevational view thereof;

FIG. 5 is a right elevational view thereof;

FIG. 6 is a top plan view thereof;

FIG. 7 is a bottom plan view thereof; and,

FIG. 8 is a perspective view similar to FIG. 1 showing the shroud and fan in exploded condition from the fin body of the heat sink. 

The ornamental design for a heat sink, as shown and described. 